Clutch



Jan. 1, 1946. C.-M. EASON 2,391,955

CLUTCH Fi led May 6, 1942 5 Sheets-Sheet 1 IN VENTOR.

Cdafeizce 05072;

C. M. EASON Jan. 1, 1946.

CLUTCH Filed May 6, 1942 5 Sheets-Sheet 2 I NVEN TOR.[ZCZ/EXZCP/WZZZU/Z,

C. M. EASON Jan. 1, 1946.

CLUTCH 5 Sheets-Sheet 3 Filed May 6, 1942 INVENTOR.

Z41 (Zara/z (a M 505072 C. M. EASON CLUTCH Jan. 1, 1946.

5 Sheets-Sheet 4 Filed May 6, 1942 m W w C. M. EASON Jan. 1, 1946.

CLUTCH Filed May 6, 1942 5 Sheets-Sheet 5 INI ENTOR. CZQIBTZCQ M [06072,

BY M02256? W Patented Jan. 1, 1946 UNITED- STATES PATENT OFFICE2,391,955 omen Clarence M. Eason, Waukesha, Wis; A piieatibniway 6,1942,Serial 1%. 441,904;

igfbiaii s. (or. 192 12) The present invention relates to clutches d-jsignedprimarilyfor driving, punch presses and such: other machines and"devices as are characterized by as single stroke operation, a singlereve lution', or other, single or limited operation While the inventionresides primarily in those features of the clutch vcontrol mechanismhaving to: do with single stroke or single trip operation of a hu chpress, nevertheless the invention is not, essentially limited theretobecause the control mechanism also includes improved features having; todo with continuous or repeated running of the press.

The present invention embodies improvements on. the clutch control:mechanism disclosed in my prior. patents: 2340;416, issuedFebi'uarylg1944', 2,348,891, issued May 16; 1944. In these prior patents theengagement of the clutch-is effected by manually actuatedmean's; such asby the depressing of. a foot treadle or like control element. Thisoperates through the clutch control mechanism to cause engagement of theclutch for starting thercycle of'the' punch press. The disengage ment ofthe clutch is thereafter efiectedby power actuated means which is powerdrivento move in synchronized relation to the motion or the ram or crankshaft of the punch press: When this power actuator starts todisengagethe clutch it assumes complete control of the clutch and compelsdisengagement thereof irrespective of any'lpositi'on or motion that themanually actu' ated, means may take. Thus; when theclutch controlmechanism is set to cause single stroke operation .of the punch presseach time that the footytreadle is depressed, any failure to release thefoottreadl'e' with sufficient quickness does not permit the punch pressto make a second stroke or repeated strokes until the treadle' isreleased. To the contrary, the power actuator assumes dominant control?and compels the clutch to release for stopping the press at the end ofthe single stroke operation; This feature" is of decided:importanceibecause of the continuous trend toward higher and higherpress speeds. This trend; toward higher press speeds (approachingIQQOYR. P. M.) has been particularly accentuated ofjlate by warproduction requirements, and these higher speeds have greatlycomplicated the control of punch press clutches. For example, whenoperating an older type of punch press under the relatively slowerspeeds of approximately 100' to 150 R; P. heretofore prevailing inh'eavyduty Work; it was not diificult' for the operator to depress thetripping: treadle for causing: a single stroke-operation; and to thenquicklyre'move' his foot from the treadle before: another singlestrokeoperation could start'. However, when operating a press at considerably.higher speeds, approachirig 10003.. P. Mi, it is physically impossiblefor the operator to depress. the. tripping pedal through its full rangeof movement for jcal sing a single stroke operation, and,,still.g.et hisfeet off the treadle quickly enoughto prevent another cycle ofoperation; Accordingly, greater hazards are introduced into theoperation of; the clutch control mechanismbythesehigher speeds.

The construction disclosed in the present: application is an improvementupon the constructions disclosed in my aforementionedrprior pate ents innumerous respects; particularly in that the clutch control member, themanual actuator, and the power actuator areall uniquely arranged forrotary oscillatory motion instead of operating with an endwisereciprocatory. motion. The clutch control mechanism of the presentapplication is rnuch more definite; positive and reliable in 'itsoperation than thev clutch. control mechanisms of my priorpatents.Moreover, it can be constructed and assembled more cheaply and in ashorter length of time; 7

Another feature of the present invention re-.- sides in the inclusion ofthis improved'constr'uction of control apparatus in friction clutcheswhich utilize torque responsive servo-mechanisms for securing highengaging pressures of the clutch. v 7

Another feature of the invntion resides in the inclusion or this improed control apparatus in clutches utilizing power responsive thrustingmechanism for releasing the clutch;

Another feature or the inventionresides in the inclusion of thisimproved control apparatus in clutches utilizing fricti'on brakemechanism for governing the shifting of the shiftable clutch ele-Another feature" of the invention resides in a unique operating;arrangement of dual brakes, one brake for releasing the clutch and'theother for stoppping the crank" shaft. The operating control for theclutch releasing lorakecan be made to function as a; common brakeoperator for both brakes through a novel selector arrange ment whichenables the crank shaft stopping brake to be connected to ordisconnected from said common operator at will.

Other features, ob'je'cts and-advantages of the invention will appearfrom the followingdetail description of one prefered embodimentthereof;In the accompanying drawings illustrating such embodiment:

Figure 1 is a longitudinal sectional view through the axis of the clutchand its control mechanism, certain of the operating parts beingfragmentarily illustrated in elevation for clarity of disclosure;

Figure 2 is the transverse sectional view corresponding approximately toa section taken on the plane of the line 2-2 of Figure 1;

Figure 3 is a transverse sectional view of the clutch control mechanismon a larger scale, corresponding to a section taken approximately on theplane of the line 33 of Figure 1;

Figure 4 is a fragmentary view similar to Figure 3, showing a furtherstep in the single stroke operating cycle;

Figure 5 is a view similar to Figures 3 and 4,. showing an operatingstep in the repeating cycle of the clutch control mechanism;

Figure 6 is a developed sectional view for the purpose of showing theservo mechanism and the ball-cam mechanism; and

Figures '7, 8, 9, 10 and 11 are detail views of different parts of themechanism.

Referring first to Figure 1, the adjacent side portion and end bearingof the punch press is indicated fragmentarily at 24, the crank shaft isindicated at 25, the crank at and the flywheel, belt wheel, bull gear orother driving element is indicated at 26. In the case of a back gearedpress, the shaft 25 may be a countershaft in the train of back gearing,instead of being a crank shaft. The hub portion 21 of said belt wheel orflywheel is journaled on the reduced outer end of the crank shaftthrough the medium of thrust resisting anti-friction beares 28. Thedriving element of the clutch comprises a female cone member 3| which issecured to the belt wheel 26. The driven element of the clutch comprisesa coacting male cone 32a, this being shiftable axially for effectingclutch engagement with the non-shiftable female cone 3|. The shiftablemale cone is one part of an assembly which makes up the shiftable clutchelement, and which I have designated 32 in its entirety. Any suitableclutch lining material 33 is riveted, brazed or otherwise secured to themale cone 32a.

The shiftable clutch element 32 comprises a hollow hub structure 34which is rigidly secured to a servo strut ring 36. Also housed withinthe relatively large hub 34 is a companion servo strut ring 31 whichcooperates with the first named I strut ring 36, the hub 34 being freeto rotate relatively to the latter ring 31. In the preferredconstruction, the servo ring 36 has its outer periphery formed with aplurality of longitudinally extending external splines 38 of gear toothform. and the hub 34 has a corresponding series of internal splines 39projecting inwardly therefrom for interfitting engagement with theexternal splines 38; although a keyed or any ot er locking relation maybe established between the hub 34 and ring 36 if desired. The two servorings 36 and 31 are mounted in side by side relation on the outersurface of a flanged hub 4| which is rigidly anchored to the shaft 25 bya .drive key 43 and by a tight fit on a tapered portion of such shaft.The ring 36, which functions as a driving ring for the servo mechanism,is free to rotate on the hub 4| and also to shift axially along saidsleeve in response to the shifting force exerted by the toggle strutservo mechanism, as I shall presently describe. The other ring 31, whichfunctions as the driven rin of the toggle strut servo mechanism, issecured fast to the flanged hub 4| so that it is held against any rotaryor shifting motion relatively to said sleeve. The preferred method ofsecuring the driven ring 31 to the hub 4| is to provide this portion ofthe hub with external splines of gear tooth form similar to the splines38, and to provide the ring 31 with internal splines of gear tooth form,similar to the splines 39, for interfitting engagement with the externalsplines on the hub. An internally threaded thrust collar 44 screws overa, thread 45 on the shaft 25 and holds the hub 4| on the tapered portionof the shaft, and also retains the toggle strut driven ring 31 againstaxial movement. The thrust collar 44 may be locked in any adjustedposition by one or more cap screws 46 passing through holes in thecollar and threading into tapped holes in the driven ring 31.

In the preferred construction illustrated, the toggle strut type ofservo mechanism is employed, such as is illustrated in my prior PatentsNos. 2,308,679, 2,308,680, 2,340,416, and 2,348,891. However, ifdesired, the helical spline type of servo mechanism illustrated in myprior Patent No. 2,268,578, issued January 6, 1942, may also be employedin this improved clutch structure. Still further, the torque responsiveservo mechanism need not be employed in the clutch structure, but theclutch may be of any spring loaded type such as is illustrated in Figure19 of my prior Patent No. 2,340,416. Referring again to the improvedconstruction utilizing the toggle strut servo mechanism, as shown inFigure 1, the opposing faces Of the servo rings 36 and 31 are formedwith pairs of cooperating substantially spherical sockets 48a and 49afor receiving toggle struts 5|, and these opposing faces of the servorings are also formed with cooperating pairs of substantially sphericalsockets 48b and 49b for receiving reverse driving spring struts 52. Theforward driving struts 5| and the reverse driving struts 52 are solidfixed-length steel units having relatively large spherical end headswhich are accurately machined and ground for transmitting highcompressive thrust loads through such end heads. The spherical sockets48a, 48b and 49a, 491) are also accurately machined and ground, and arepreferably of a slightly larger radius than the spherical ends of thestruts. The fact that the two servo rings 36 and 31 are entirelyseparable from other parts of the clutch structure facilitates theoperation of forming these spherical sockets. A relatively lightcompression spring 53 encircles each spring strut 52 and has its endsbearing against thrust shoulders substantially at the outer ends of thespherical sockets 48b and 491).

There are preferably three pairs of such driving and spring struts 5|and 52 arranged in equidistant angular spacing between the servo rings36 and 31. Of course, any desired number of pairs may be employed butthree pairs afford a three-point application of the spring pressure andalso of the servo pressure. The struts are preferably set at theinclined or helical angles respectively illustrated in Figure 6, thehelical angle of each strut representing an angular relation of thestrut with respect to the axial line of the clutch. The forward drivingstruts 5| are all inclined at the same common angle with respect to theaxial line, and the reverse driving spring struts are all reversely oroppositely inclined at the same common angle with respect to this axialline. In the embodiment illustrated, this angular inclination isofsubstantially the same degree-for both sets of struts, although: thetwo sets maybe disposedat considerably. different angles, if desired.The degree of engaging pres sure ultimately established in the clutch bythe servo action of the struts can be proportioned'as clesiredby varyingthe angular'in'clinationof the struts. For example, as the angle ofinclination of the struts it is made to approach the plane of rotationthe servo action diminishes, and as the angle of inclination is made toapproach the axial'plane, the servo action increases.

With reference to the springstruts 52, the springs of these strutsfunction as the loading springs which normally tend toforce the shift"-able clutch element 32 into engagement with the nonshiftable clutchelement 31. It will be observed that by virtue of their inclinedpositions; these struts impart an axial component and a rotatingcomponent to the shiftable clut'cli element. The axial component isrurther-supp1e-- mented by the toggle action of the driving struts 5|when transmitting a driving load. The normal direction of rotation ofthe clutch and crank shaft is indicated by the arrow 1. It will be notedthat the spring struts tend to produce relative rotation between thedriven clutch element 32 and the sleeve 41 in opposite directions; i; e.they tend to rotate the driven clutch element in the forward directionof rotation r and, at the same time, they tend to rotate the sleeve Mand the connected crank shaft 2-5 in" the reverse direction of rotation.It is the compression springs on these spring struts 52 that are placedin the loaded or cocked condition by the inertia of the crank shaft andits connected parts" when the clutch is disengaged; and which normallystand ready to effect engagement of the clutch instantly upon thetripping operation. As fully discussed in my aforementioned priorpatents, these spring struts can also function as reverse drive struts.It is frequently desirable to be able to back up the press ram duringthe operation of changing or setting the dies, or freeing the movabledies from a jammed conditionin the work, and such can be readilyaccomplished in wheel 26' and driving cone- 31 inwardly or outwardlywith respect'to the shaft driven clutch element 32 and thrust reactionsleeve member 31, M; This shifting adjustment of the-flywheel iseffected by providing the outer end of the flywheel hub 21 with arelatively heavy internal thread 56 which is adapted to'screw over a"thread 51 formed on an inner adjusting sleeve 58. The internal thread 55may be formed directly in the body of the hub 21, although forfac'ility'of niachining andhandling I preferably form the thread on aseparate sleeve 55 which is pressed and pinned into the flywheel hub21-. A thrust sustaining coupling 5B6l serves to mount the externallythreaded sleeve 58' on the end'of the shaft 55 in such relationthat thesleeve 58- can rotate relatively to the shaft but cannot shift endwisein either direction relatively thereto. As shown in Figures '7 and 8,this thrust sustaining coupling comprises the two duplicate couplinghalves 6 0 and 6| each formed wi'th one-half of arr-annular groove 62:;and one-half: of an inward lyex'tending flarigeta:v Thetwo couplinghalves areassembled'radially over theend of the crank shaft- 25, the twohalves of they inner flange 63 fitting intoan annular} groove es formedin the shaft; and the: two halvesof the internal groove Mi'fitting over.anendflan'ge Biformedatthe ex.- tremity. of the shaft. After thetwo-halves of the coupling have thus been assembled. over opposite sidesof the'shaft, the internalbore 61 ofthe manually;actuate'dadjustingiring- 58'- is' passed over the-coupling halves, as:shown in Figure 1;. Cap screwsfit are then passed inwardlythroughopenin'g's the web or the adjusting ring 58; and arethreaded intotapped. holes formed in the outer flange portions- 69 of; the couplinghalves, these screws fixedly securingthe adjusting ring- 58 againstoutward separation fromthe coupling halves 60, SI. It will be evidentthat rotation ofthe ring 58' within the internally threaded oompanionring 551s operative to cause the latter ring to screw back and forthalong the threadL 5-1 for causing the flywheel and driving clutch elemerit to slide inwardly or outwardly along: the shaft 25. A simple form"of automatically releas able detent' mechanism isiprovided' forlockingthe adjusting ring 58 in" any-position ofadjustment; This detentmechanisin=- comprises" a pair-ofdir' ametrically opposite lockingplungers H having slidable mounting in diametrically opposite bores inthe endof the-flywheel hub, springs 13in these bores normally urging theplunger-s: outwardly intoilocking position. Reduced ends 'H' ontheplu-ng'ers' are adapted t6 snap into diametrically opposite pairs of.holes M formed in a flange 15 extending radially from the adjusting ring58: The adjustment of the clutch is performed by a. spanner wrench ofthe general: construction ile lustrated in Figure 9; This comprises across bar 7'! from the central portion of which projects two pins 18which are receivable in the diametri= cally opposite openings- M- forreleasing the de---: tent" plungers Tl. The mere act of' introducing thepins into the openings 1 automatically re leases the detent plun'gers sothat the adjusting ring 5-8 can b'e'rotate'd in' either direction though a distance equal t'o-the spacing between diametrically oppositepairs of openings M. As soon as the next pair of openings 14- comes.into'line with the" detent plungers H the locked relation is'automatically' restored, this serving to apprise the attendantof-the-fac't that the clutch has been adjusted through a unit degree ofadjustment. The total range of adjustment may be extended throughseveral" of these units ofadjustment.

Inter-posed between the clutch structure and the frame of the press isthe rotary thrusting mechanism which utilizes the rotational motion ofthe driven clutch element 32 for compelling this clutch element todisengage itself from the driving clutch element 31. This thrustingmech-- anism comprises" the ring 36; a companion ring 81 disposed on theinner side thereof, and a series of balls 82 disposed between" the rings36' and Bi As shown in section in Figure 6, the opposing faces of thetwo rings on plates 36 and 81 are formed with coacting cam track runways83 and 84* for" each of the balls 82. The twocam rings 36 and B l arecapable of relative rotation, as by interrupting the rotation of thering 8t, and such relative rotation operates through the'balls andsloping runways 83 and'-84 to create a spreading or separating pressurebetween the two rings for shifting the shiftable cluteh element 32 toits disengaged position and for holding it i n this disengaged position.As previously described, the ring 36 is fixedly secured to the shiftableclutch element 32 so that these two parts rotate and shift together,whereby outward shifting force exerted against said ring 36 istransmitted directly to the clutch element 32 for shifting the latter todisengaged position. The other cam ring 8| is also capable of rotarymovement but this ring is fixed against axial shifting movement in aninward direction. To this end, a series of anti-friction thrust balls 86roll between an externally grooved inner race 81 and an internal racewayin the ring 8 the inner race 81 abutting a shoulder 89 on the flangedhub 4| and holding the cam ring 8| against inward shifting movement.There are preferably three sets of thrust balls 82 and cam pockets 83and 84 disposed at spaced points around the rings 36 and 8|, as clearlyshown in Figure 2.

The outer end of the race ring 81 projects beyond the cam ring 8| toform a stop shoulder 99 which limits the shifting movement of the servoring 36 to the left and hence prevents the possibility of the togglestrut servo mechanism 5|, 52 overloading the clutch shifting balls 82and the thrust sustaining balls 86. Thus, any short-circuiting of thetoggle strut servo ring 36 is always borne on the stop surface 90. Insuch short-circuiting or overload release, the thrust forces of thetoggle struts are confined or self-contained within the clutchstructure, being transmitted from the toggle struts through the innerservo ring 36, stop shoulder 90, ring 81, shoulder 89, flanged hub 4|,shaft 25, threaded ring 44 and outer servo ring 31 back to the togglestruts. A certain amount of resiliency is inherent in the yieldabledriven cone 32a, and this provides for a spring loading of both frictioncones. Adjustment of the slip point or the point of overload release canbe quickly and easily effected by axially shifting the flywheel 26 anddriving cone 3| relatively to the driven cone 32, through rotation ofthe manually actuated adjusting ring 58 by spanner wrench 11, aspreviously described. In making such adjustment, a small amount of yieldgives relativel low torque capacity and a large amount of yield givesrelatively high torque capacity.

The shiftable driven clutch element 32 is adapted to be shifted toclutch releasing position by exerting braking retardation against therotary motion of the cam ring 8 I, whereby the continued forwardrotation of the other cam ring 36, clutch element 32 and crank shaft 25causes the balls 82 to roll up into the shallow ends of the pockets 83and 84 for exerting lateral separating force between the rings 36 and8|, such separating force shifting the clutch element 32 to thedisengaged position. The braking retardation is exerted on the ring 8|through an annular brake drum 9|. Disposed alongside the drum 9| in backto back relation is a companion brake drum 9| which is substantially aduplicate of the drum 9|. This companion drum 9| is adapted to applybraking retardation to the crank shaft 25 for bringing the latter torest immediately upon releasing the friction clutch 3|, 32, and forholding the crank shaft with the crank 25' in proper elevated positionuntil the clutch is again engaged. The brake shoes and other associatedparts used in conjunction with the brake drum 9| are duplicated for thecompanion brake drum 9|, and in both cases the same reference numeralswill be employed to appended to the numerals designating the partsassociated with brake drum 9|. The two drums are preferably constructedof sheet metal, and the drum 9| is secured by rivets 92 to the ring ll,whereas the other drum 9| is secured by rivets 92' to a radial endflange 93 extending outwardly from the inner end of the sleeve 4|. Bymaking the two brake drums of dished sheet metal construction anddisposing them back to back, different portions of the mechanism can beextended into the hollow interiors of the two drums, thereb making theassembly of shorter axial length. Mounted within the open front of theouter brake drum 9| is a combined brake lockout and safety lug plunger94. This plunger is guided 'for inward and outward reciprocation in aguide bushing or bracket 95 suitably secured within the peripher of thebrake drum. The inner end of the plunger is guided in a hole 96 in theweb of the brake drum 9|, and this end of the plunger is adapted to beprojected into a. corresponding locking hole 96 formed in the web of theother brake drum 9|. When the brake is engaged and the clutch isreleased the holes 98, 96 are in alignment and the inward projection ofthe plunger 94 into the hole of the inner drum serves to lock the twobrake drums together. When the drums are thus locked together, the brakecan be released without engaging the clutch. Normally the brakemechanism is operative only to release the clutch and to stop rotationof the crank shaft (1. e. with the crank in the upper dead centerposition), but when the two brake drums are thus locked together thebrake is usable at any point in the 360 rotation of the crank shaft.This is often advantageous during the operation of changing dies,adjusting dies, etc., when it may be desirable to slowly move the crankshaft forwardly or backwardly with 40 the clutch 3|, 32 released andwith the brake the front edge of the brake drum 9| is adapted designateduplicate parts, with the prime suflix 7 to function as the safety stoplug, as I shall presently describe.

Referring to the other brake drum 9|, there is mounted within the openrear face of this brake drum an adjustable eccentric |0| which drivesthe power actuator for controlling the automatic releasing of theclutch. This eccentric encircles the crank shaft 25 in separatedrelation therefrom so as to be angularly adjustable relatively to thecrank shaft. A cup-shaped flange I62 extends outwardly from theeccentric and then extends forwardly to embrace the end flang 93 on thedrive sleeve 4|.- A plurality of angularly spaced threaded bossesproject outwardly from the flange I02 for receiving set screws I93 whichthread radially inwardly for entering selected ones of a plurality ofsockets formed around the exterior of the flange 93. It will be apparentthat by loosening the set screws I03 the eccentric |0| can be angularlyadjusted relatively to the flange 93 of drive sleeve 4|, and thenrefastened to the flange 93 by the set screws I03. This change ofangular position of the eccentric |D| relatively to the crank 25 ofcrank shaft 25isfortheipurposeaof adapting-the clutch mechanism :todifferent press speeds. For example, the power release of theclutch'must be initiated at an earlier'point in the-cycledn the case ofhigh press speeds.

Referring to Figure 2, the clutch controlling brake drum 9I is embracedby twoarcuate'brake shoes I05, I56, and it will=be understoodthat thecompanionbrake drum9 I in rear of; the drum :9I is embraced by acorresponding :pair of brake shoes I95 and I96. Each of thesebrakeshoes-is lined with any suitable=brake lining'material-Ifl'l. Theupper ends of the two ,apai'rs of'brakeshoes are pivotally mounted onstationary moimt'i'ng pins I68 and I09 projecting outwardly from abracket III secured to'the-pressframel i. The lower ends of-each pairof'brake shoes are normally forced toward each' other through the actionof spring mounting rodsl I 2, I I2. Each rod extends through bosses II3,H4 formed 'on the lower portions of their associated brake shoes. Oneend of therodishea'ded for engaging against a collar I I5 havingknifeedged rockerabutment against the boss I I4. The other-end ofthe'rod is threaded for receiving a wing nut-I'IB which adjuststhe'pressure of a; compression spring :I-I'I mounted onthe rod, theinner endofz-said spring bearing against a collar H8 having knife edgedabutment against the boss II3.

Formed at the lower extremities of {the series of brake shoes are guidebosses =I2-I and 122, in which'spring take-up rods I23 are guidedforendwise movement. As shown-in Figurer 10, the inner end of-each take-uprod =I23 =is pinned or otherwise fastened in a cylindricalqhead I24which is free toslideendwisein a guide bore, I25

in-theguide boss. Atubular-guide-stem I25 has a threaded inner end-I21which screws into a thread atthe outerend of the bore 125. The-rod IE3is provided with-a long adjustingthread I28 over which screwsanadjustable stop orlimit sleeve I 29 having -a stopfiange I 3| at itslower end adapted to abut the under side ofthe guide stem head I21.Mountedion-the outer-end of said stop or limit sleeve I29 is a hex-headnut or collar I32 which is held against rotation on -thesleevebyforming-thesleeve with-a splayed surfac -I3-3 and-formingthehex-head collar with a D-shaped opening having. a matching-fiatsurface engaging this splayedsurface. A spring centering washer I34bears'against the underside of the collar I32 and centers the outer endof a-relatively light compression spring 435, the inner end ofwhichspringbears-against the threaded end -head I21 of the stem I26. Byrotating the a on which are mounted a pairnf parallel-toggle links -I-4Idisposed in side by side relation. I The inner endsof these toggle linksarezpivotally mounted on a knuckle vpivot .142 extending through one ofythe-side :arms'of the iTr-ishaped rocker member I44. The. inner endtofeach guidesboss I;2 I has arcuategrecesses I45 formed thereiniorreceiving :the r cylindrical bearing portions I46 formed on 'theguideportion I24.

.The-togglerockerIMis secured to a rock shaft I148 which oscillates therocker back and forth between the brake engaging position illustrated invfulllinesland the brake releasing position illustrated in dotted lines.In the brake engaging position shown in fulllines the knuckle pivot I42occupiesja position considerably below the line of dead'centeralignment-extending between the axes of pivot pin I38 and rock shaftI48. 'In this position'of the parts the relatively heavy pressure of thebrake engaging spring III is operative to force the brake shoes I05 andI06 into firm braking engagementcwiththe drum 9|. When the tog le rockerA44 is swung into the dotted line position the knucklefpivot I42 iscarried through and slightly'beyond the line of dead center alignmentextending between the axes of pin I38 and shaft I48. This exerts outwardthrusting force through the toggle links 'I4I- for releasing the brakeshoes from' thebrake drum. In the reverse operation. of engagingthebrake shoes, thereturn oscillation'ofthe toggle rocker into its fullline position break 1the'o'ver center locking relation ofxthe togglelinks -I,4I and permits the brake spring III to :set the brake shoes.take-up action which can. now occur between the guide-head I2'4 and theguidesleeve I21 in oppositiorrto therelatively light pressure of-thespring I35 results .in a take-up or equalizing relation between all ofthe bra'keishoes. As hereinafter described, thetwobrake shoes I05 andI06 for the other brake drum. 9| are actuated through an identical.:form of toggle rocker I44 serving to control the brake shoesthrough anidentical arrangementof Spring rods I23, guide heads I24, tQggle linksI, etc. I-Ience, under normal operating conditions or undermost-operating conditions the two pairs .of brake'shoes engage theirrespective brake drwns-substantially simultaneously and release theirrespective brake drums substantially simultaneously. Accordingly, fourbrake shoes have concurrent operation through their respective togglerockers I44, I44 and rock shaft I48. .The spring take-uporequalizingrelation: described-above permits .the take-up rod I23 tocontinue to move inwardly'with continued rocking movement-of-the togglerockers even after the brake shoe-ofthattake-uprodhas come into firmbraking engagement with its brakedrum. Thus, if one brake shoe engages;its brake drum substantiallyin -advance o f the other three brake shoes,

that fact will .notstop continued swinging movementfpf thetogglerockers-under the pressure of therelatively heavy springs-Ill.This-makes sure lthataltfour;brake shoes willengage their brake Idrumswith substantially the same or-equalized pressures. In :theabsenceof-such equalizing arrangement the toggle linkagemight result in onebrake shoe bearing with considerable pressure .against itstbrake t drumwhile the other three brake shoes-had very little'or n'o firm bearingengagement against the brake drums. In this regard, the-provisionof theinward and outward adjustment' jofjthe .end of each brake shoe along thelength of its respective spring take-up rod I23 serves the. further'purpose of enabling different 'tirningadjustments to'b'e'had betweenthetwo brakenrums. That is to say, the timing of the engagement'ofthejbrake shoes may be adjusted so that the-outer brake drum 9 I whichcontrols {the {clutch can f be "released ahead of the inner brake drum=9 I which releases the crank shaft.

The spring This difference of timing, which can be had if desired,avoids any possibility of the crank shaft 25 starting to run backwardlyunder the pressure of the reverse drive toggle springs 53 before theclutch 3I32 becomes engaged for transmitting forward rotation to thecrank shaft. This adjustable relation also enables one or both innershoes I95, I66 to be adjusted to exert a slight constant drag on thecrankshaft brake drum 9|. Furthermore, the adjustable relation enablesthe brake shoes to be adjusted to compensate for wear of their brakelinings I01.

Referring now to the clutch control mechanism which rocks the rock shaftI48 for selectively causing single trip or single stroke operation orrepeating operation of the press as desired, it will be seen from Figure1 that the rock shaft is journaled in a housing II which is suitablysecured to the press frame 24. The main body portion of the rock shaftI48 is longitudinally splined, and the outer toggle rocker I44 hassplined engagement therewith which compels this member to rock with theshaft. The other toggle rocker I44 for controlling the crank shaft brakedrum 9I' is free to oscillate on a sleeve I54 which is splined to therock shaft. Provision is made for releas ably coupling this inner togglerocker I44 to the outer toggle rocker I44, whereby the brake mechanismfor the crank shaft may be made to operate concurrently with the brakemechanism for en gaging the clutch, or the brake mechanism for the crankshaft may be made non-functioning in the sense that it merely imposes alight frictional drag on the crank shaft at all times to preventcoasting or overthrow of the crank and ram. This releasable couplingmeans for selectively coupling the two toggle rockers together comprisesa plunger rod I55 mounted for sliding reciprocation in a guide sleeveI56 carried by the rocker I44. A spring I51 tends to thrust the couplingplunger in an inward direction for engaging in a coupling aperture I58in the other toggle rocker I44. An angularly bent handle I59 at theouter end of the plunger rod is adapted 'to be placed in the downwardlyextending position shown when the rod is moved inwardly to couplingposition. To release the coupling engagement, the handle I59 is pulledoutwardly'to withdraw the plunger I55 from the hole I58, whereupon thehandle is revolved upwardly to engage against the outerretaining-shoulder I6I at the outer end of the guide sleeve I56.

The housing I5I is provided with a removable cover plate I52 whichcarries an anti-friction bearing I62 supporting the reduced inner endI48 of the rock shaft I48. Rocking motion is imparted to the rock shaftthrough the medium of a crank I64 which has a splined hub engaging overthe splines of the rock shaft. Thi hub has rotatable bearing support ina bearing bushing I65 supported in a bearing boss extending from theouter wall of the housing I5I, Projecting laterally from the lower endof this clutch controlling crank I 64 is a crank pin I64 carrying asuitable anti-friction needle bearing on which is mounted a double nosepawl I 66. The clutch controlling crank arm I64 has a relatively limitedback and forth oscillation between the left hand position shown inFigure 3 and the right hand position shown in Figure 4. The double nosepawl I66 is, ofcourse, carried bodily with the oscillatory motion of thecrank I64 and crank pin I64, and, in addition, this pawl I66 has alimited oscillatory throw around the axis of the crank pin I64". Anover-center snap motion i imparted to the double nose pawl I66 by theaction of an over-center spring strut indicated generally at I61. Asbest shown in Figure 11, this spring strut or biasing spring assemblycomprises an upper guide rod section I68 having an apertured upper headI69 which has pivotal mounting on a pin I1I projecting laterally fromthe lower end of the pawl I66. This upper guide rod section has atelescopic sliding fit within a lower guide sleeve section I12 formedwith an apertured head I13 at its lower end, which head has swingingmounting on a stationary pivot pin I14 disposed generally below the rockshaft, crank arm and pawl. A helical compression spring I15 surroundsthe rod I68 and sleeve I12 and has its ends bearing against the upperand lower heads I69 and I13. The action of this over-center togglespring is to urge the pawl and crank arm to a completion of theirmovements in either direction, this spring reversing its bias andtending to cause completion of the pivotal movement in the oppositedirection as soon as the axis of the upper knuckle pivot I1| passesbeyond the center line z-z of Figure 3. The opposite or inner end of theknuckle pin I1I terminates in a rectangular block I16 which projectslaterally from the inner side of the pawl I66,

said block functioning as a stop surface adapted to be engaged by aninterrupter pawl, as I shall later describe.

The left hand nose I66 of the pawl I66 is adapted to have motionimparted thereto by a manual actuator indicated generally at I18, andthe right hand nose I66" of said pawl is adapted to have motion impartedthereto by a power actuator indicated generally at I19. These twoactuators comprise rotatable collars disposed in side by side relationand both mounted for oscillatory movement about the axis of the rockshaft I48. As shown in Figure 1, suitable anti-friction bearings II arepreferably interposed between these actuators and the reduced inner endI48 of the rock shaft. The manual actuator I18 is formed with a radiallyprojecting lug to which is anchored a block I 18a which projects axiallytoward the power actuator I19. This block I18a is adapted to engage theleft hand nose I66 of the double nose pawl. Similarly, the poweractuator I19 has a radially extending lug to which is anchored a blockI19a which projects axially toward the manual actuator. This latterblock I19a is adapted to engage the right hand nose I66 of the doublenose pawl, As best shown in Figure 1, the double nose pawl ismounted ina plane lying directly between the planes of the actuators I18 and I19so that the two noses of said pawl are in a position to be actuatedalternately by the actuator blocks I18a and H901. When either nose ofthe pawl is pressed inwardly against the actuators by the over-centerspring I61 the upper extremity of that pawl nose rides on matchingperipheral surfaces I82 of both actuators, as clearly shown in Figure 1.

An arm projecting outwardly from the manual actuator I18 carries a pivotbolt I84 which establishes pivotal connection with the upper end of avertically reciprocatin link I85. The link ex-. tends down through aslot in' the bottom of the housing I 5I and carries a pivot bolt I86 atits lower end for establishing pivotal connection with one end of arocker lever I81. Said lever is pivoted on a stationary fulcrum pivot I88 projecting from the frame I5I and the other arm of said lever ispivotally connected at I89 with a link I 9| extending down to a foottreadle or like tripping member, not shown. The operating relation issuch that when; the treadle or other tripping member isactuatedto causethe press to operate, a downward pull is transmitted through link I9I tolever I81 for thrusting the other link I85 in an upward direction. Thisoscillates the manualactuator I18 in a counterclockwise direction forthrowing the clutch control member I54 and pawl I66- toward the right(Figure-4), as will be later described in detail. The lower portionofthe actuating link I85 carries a laterally projecting lifting pin I92adapted to raise an intercepting dog I93 from the lower position shownin Figure 3-t0 the upper-positionsshown in Figures 4 and 5. Said: dog orpawl I94 has an upwardly extending stop shoulder I94 which liesentirely'belo'w the path of movement of interrupter block I16onthedouble nose pawl I69 when the interrupter pawl I93- is in the lowerposition shown in Figure 3, but which stopshoulder'is swung upwardly toa point where it caninterrupt motion of said block I16 when the dog I93is lifted up to the position shown in Figure 5. The intercepting dog I93swings up and down around the axis of a pivot pin I95 which islaterallyshiftable or displaceable for shifting the dog I93 from thenonintercepting position shown in Figure 4 to the intercepting positionshown in Figure 5. This pin I95 projectseccentrically from the end of acylindrical mounting pintle I96-which is journaled in a bearing boss I91formed in the housing II An operating handle I98 is secured to the outerend of'said mounting pintle I96 and, if desired, one side of this handlemay be provided with the inscription Single stroke on one side of thehandle adapted to be presented to view when the handle is swungdownwardly to the full line position shown in Figure 1, and the otherside of the handle may be provided with the inscription Repeating whichwill be presented to view when the handle is swung upwardly to thedotted line position shown in Figure 5. Referring particularly toFigures 3 and 4', when the selecting handle I98 is swung downwardly, asindicated in dotted lines in these figures, theshiftable pivot I95occupies a position displaced toward the right. Hence, when theintercepting dog I93 is lifted upwardly from the position shown inFigure 3 to the position shown in Figure 4 theshoulder I94 of this dogis incapable of performing any intercepting function, i. e., it-isincapable of interrupting any part of the travel of the interrupterblock I16, owing to the fact that said stop shoulder has now beenshifted sufliciently far to the right'so that the clutch control memberI64-and pawl I66 reach the limit of their movement toward the rightbefore the interrupter block I16 engages the stop shoulder I94. Hence,the double nose pawl I66 is free to complete its full-range ofoscillatory movement into the position shown in Figure 4, in whichposition the right hand nose I66 of the pawl is positioned at a pointwhere the power actuator block I19a will strike said nose and impartmovement to the pawl in the oscillation of said power actuator I19.Conversely, when the repeatingselection is made byswinging the handleI98 upwardly to the position indicated in dotted lines in Figure 5, theshiftable pivot I95 is, displaced to the left sufiiciently far so thatwhen the interrupting dog I93 is lifted to its motion interruptingposition the stop shoulder I 94 will be so disposed in the path ofmovementof the interrupter block I16 that motion of the lower end of thedouble nose pawl I66 will. be interrupted I before the oscillatorycontrol member I64'reaches;the limit of itsmovement. Hence, the doublenose pawl is oscillated in a clockwise direction about the crank pinIlill' fori swinging the right hand nose I66 downwardly. to a positionwhere it lies out ofthe path of-th' power actuator block I19a. At thistime, the power actuator is incapable of imparting motion through themotion transmitting pawl I66-to the clutch control member I64 and hencethe clutch remains engaged for causing a repeating opera tion of thepress, as will hereinafter-appear in the description of thecycle ofoperations.

As best shown in Figure 3; the power actuator I19 has a laterallyextending arm which carries a pivot bolt 29! for establishing pivotalconnection with a reciprocating linki tz. Said link functions as thepitman or connecting rod for an eccentric follower 203'which surroundstheeccentric Hit (Figure 1-). The eccentric follower. is provided-with adownwardly extending threaded boss 294 in which a threaded upper end ofthe link 292 has adjustable mounting. It will be understood that eachrevolution of the crank shaft 25 will transmit a cycle of up anddownoscillatory movement to the poweractuator I19,

which up and down oscillation can be adjusted v The throw of the clutchcontrol member- I64 toward the right is limited by a stop surface 296 onthis member coming-upagai'nst anadjustable stop bolt 291, asshown inFigure 4. Thisstop bolt 291 has threaded mounting in a boss 29-8projecting inwardly from the outer wallof the housing I5I, saidboltbeing locked inany adjusted position by the lock nut- 299. This stop 291serves to limit the motion of the toggle parts I4I, I44 in theirbrake-releasing, clutch-engaging direction of movement. That is to say,this stop 291 serves to stop the toggle rocker I44 with the knucklepivots I42 disposed substantiallyin dead center alignment or at anydesired degree past this position of dead-center alignment Another stopbolt 2II is mounted in a threaded bossZlZ in the upper wall of thehousing 154, this upper stop bolt being locked in any adjusted positionby the lock nut 2I3. Ihis upper stop bolt is adapted to be struck by theupper surface 2I4 of the reciprocating link. Hi5 that responds to foottreadle operation. This adjustable stop serves to control the range ofoscillatory movement that the foot treadle can transmit to the manualactuator in the operation oflengag-ing the clutch.

Manually actuated locking mechanism is preferably provided for thepurpose of either look-- ing the control mechanism against any possibleactuation through thefoot treadle, or for locking-the foot-treadle andmanual control parts intheir actuated position for causing acontinuously repeating operation of the press. This locking. mechanismcomprises a rotatable lock shaft 2I6-which is journaledin the side wallof the-housing I5I. A handle 2I8 on the outer end of saidlock shaft'isadapted to swing from an upper unlocked position indicated infull linesinFigure'2 to a lower locked positionindicated in dotted lines.Referring to Figure 4, the locking shaft has a diametrical slot 2 i9therethrough through which the outer edge of the reciprocat ing link Iis adapted to slide. Saidreciprocate l n s t er ieal rspa e a -Hate t hs 221 and 222'cut therein. When the link is lifted to its upper positioncorresponding to the manual tripping of the punch press, the lockingshaft 2I6 can be rotated to present its solid peripheral portion intothe notch 222 for locking the mechanism in this actuated position sothat the clutch will remain engaged and the press will continue tooperate. Conversely, when the reciprocating link I85 is in its lowerposition, the locking shaft 2I6 can be rotated to present its solidperipheral portion to the arcuate notch 22L This positively locks theclutch control mechanism against any possibility of accidental operationthrough the foot treadle, which positive locking may be employed toprevent tampering or accidental operation when no punching or drawingoperations are to be performed by the press. A lug 225 projecting fromthe right hand end of the interrupter pawl I93 is adapted to strike theshaft 2| 6 for limiting the upward movement of the pawl to the pointwhere the stop block I16 does not drag along the horizontal upper edgeof the interrupter pawl I93.

My improved clutch control mechanism also comprises mechanism for makingthe operation of the press subject to automatic electrical control,etc., or subject to the feed of material in the case of continuous feedpresses. Aplunger head 23I is guided in the lower end of a guide boss293 extending from the bottom of the casing. This plunger head actuatesa plunger rod 235 which has pivotal connection at 231 with theinterrupter dog I93. A compression spring 239 normally urges the plungerrod and interrupter dog to their lower positions. Any suitable controlmember 24I may be provided for holding the.

plunger head 23I pressed upwardly when it is desired to hold theinterrupter dog in the position shown in Figure for causing repeatingoperation of the press. The control member 24I may be the core of anelectric solenoid which is energized through an automatic controlcircuit. The opening of this control circuit in response to anydangerous condition or other condition calling for the stopping of thepress results in the deenergization of the solenoid, with the resultthat the plunger head 23I and interrupter dog move downwardly to theirlower positions for enabling the power actuator to release the clutch.The control member 24! may also be a mechanical device subject to thecontinuous feed of stock to the punch press. Thus, when the source ofstock fed to the machine comes to an end the control member 24I movesdownwardly and automatically stops the press.

M improved construction may also be provided with a positive blockingarm 25I (Figure 2) for positively stopping the rotation of the drivenclutch element in the event that this driven clutch element shouldcontinue to rotate after the clutch has been released and after thedriven clutch element has failed to come to rest within a normal spaceof travel. This positive blocking arm 25I has an inclined cam surface25I at its swinging end adapted to be engaged by the plunger 94 forforcing the arm 25I in a clockwise direction toward the center of theclutch structure. The arm is mounted on a stationary pivot 253 and isconnected through a pivot 255 with a link 25! having its lower endpivotally engaging over the projecting outer end of the guide sleeve I56 that guides the coupling plunger I55. The operating relation is suchthat when the toggle rocker I44 is swung into its brake-releasing,clutch-engaging position indicated in dotted lines the connecting link25! acts to swing the blocking arm 25I down to a point where the stopplunger 94 is free to pass above the arm 25I. However, as soon as thetoggle rocker I44 is swung counterclockwise back to its brake-engaging,clutch-releasing position illustrated in full lines in Figure 2 theconnecting link 25! functions to swing the blocking arm 25I upwardly toits operative position approximately indicated in Figure 2. If thedriven clutch element should fail to come to a stop after the clutch hasbeen disengaged and after the driven clutch element has been allowed tocoast through a relatively limited travel, then the stop plunger 94comes up against the cam surface 25I on the stop arm. In consequencethereof, the arm is swung in a clockwise direction for transmittingstill further braking effort through the toggle links MI, I 4| to thebrake shoes for increasing the braking eiTort exerted on the two brakedrums. In addition to this, the arm positively blocks continued rotationof the stop plunger 94 after this greater braking effort has beenexerted through the blocking arm. A somewhat similar form of safety stopmechanism is also disclosed in my prior application Serial No. 415,022.

I shall now briefly summarize the operation of the clutch. Assuming thatthe operator desires that the press only operate through a single strokeeach time that the foot treadle is pressed, he moves the control leverI98 down into the lower position illustrated in Figures 1, 2, 3 and 4.This shifts the intercepting dog I93 to its nonintercepting position,and thus preselects the mechanism so that only a single stroke operationwill occur. As soon as he depresses the foot treadle the manual actuatorI18 is oscillated in a counterclockwise direction (Figure 3), therebybringing actuator block II8a up against nose I66 of the motiontransmitting pawl I66 and causing the clutch control member I64 to swingcounter-clockwise toward the right. As soon as the knuckle pivot I'IIpasses beyond the dead center line 2-2 the toggle spring I61 snaps themotion transmitting pawl I66 and clutch control member I64 toward acompletion of their movements in this swinging motion toward the right.Figure 4 illustrates the completion of such swinging movement, with thestop shoulder 206 of the clutch control member abutting the stationarystop shoulder 201. At this time, the right hand nose I66 of the motiontransmitting pawl I66 occupies a position in the downward path of thepower actuator block I'I9a by reason of the fact that the motion of thepawl I66 has not been blocked or intercepted by the dog I93. Referringnow to the sequence of operations which follows the oscillation of theclutch control crank I64 from the position shown in Figure 3 to theposition shown in Figure 4, such oscillation rocks the toggle rocker I44in a clockwise direction (Figure 2) from the full line position into thedotted line position. This releases the braking engagement of tl-e brakeshoes I05, I06 and I65, I 66 from the brake drums SI, 9|. As previouslydescribed, if it is desired to release the drum 9! in advance of thedrum 9| such can be read- 1137 accomplished by appropriate adjustment ofthe limit sleeve I29 inwardly or outwardly along the thread I28 of rodI23 (Figure 10) at each of the respective brake shoes. The release ofthe clutch controlling brake drum 9I permits this drum to start rotatingahead, largely from the rotative component Which the axial thrustingpressure transmits through the balls 82 and inclined pockets 83, 84 tothe ring 8|. As a result ofthis forward rotation. of-the brakev drum SIand ring 3f, the toggle strut'ring 36is free; to,-

load immediately creates a greatly increased.

shifting force for forcing the driven clutchelement into a very highpressure engagement. with the driving clutch element 3i.

The crank 25" and connected ram of the press start downwardly as soon asthe crank shaft begins rotating, and the high pressure engagement of theclutch is completed" by the toggle struts 5t either before the movingdiestrikes, thework or during the time that the moving die is firstengaging the work and building; up a, large torque load. After theperformance of the punching or drawing operation, the control mechanismstarts the reverse operation of releasing-the clutch. The eccentricIil'I is rotating directly with the crank haft, and at av particular'point in such rotation the eccentric starts a downward throw of theeccentric follower 263, with resulting clockwise oscillation of thepower actuator I19. When the press is operating at a very high drivingspeed, the time delays incident to inertia of the parts, play, etc;, maynecessitate that the eccentric I Ill be adjusted to start this clockwiseoscillation of the power actuator I19 even before the movable dieengages th work. brings the actuator block II9a into engagement withtheright hand nose I66 of the motion transmitting pawl I66 and startsmoving the paw1 and clutch control member I64 in a clockwise directiontoward the. left. As soon as the knuckle pivot I'II passes beyond thedead center line 2-2 (Figure 3) the biasing spring I6! completes thmotion of these parts in this direction, snapping the motiontransmitting pawl and the clutch control member over into their normalpositions illustrated in Figure 3; Referring to Figure 2, as soon as theknuckle pivot I42 moves down below the dead center line xw the pressureof the brake springs I I1, H1 is effective to accelerate the motion ofthe toggle rockers I M, M4" for quickly bringing the brake shoes intoengagement with their respective brake drums 9!, SI". The exertion ofbraking retardatio-n against brake drum SI decelerates and stops ballcam ring 8! and causes the ball cam mechanism 3284 to move the togglestrut ring 36 toward the right. 'I'h'isshifts the shiftable clutchelement 32 into clutch releasing position for stopping further drive tothe crank shaft. Concurrentlptherewith, the braking retardation imposedon the other brake drum" SI is bringing the crank shaft 25 to rest, thecrank shaft com ing to a stop with the crank 25' and ram approximatelyin the upper dead center position. Any-accidental failur of the crankshaft to stop substantially at this point brings the rotating stop 94into engagement with the positive blocking lever 25I, whereby to imposeadditional braking pressure on the brake drum 9| and, finally, to.positively block further rotative movement of the stop 94'.

If the press speed should be so high that the operator cannot removehis. footfrom the treadle' before'the completion of the cycle, or if: heshould Such clockwise oscillation quickly carelessly keep his foot onthe-treadle, this, cannot possibly causea repeating operation becausethepawl I66 still completes its clutch, releasing throw to the, left.The, nose I66 of the pawl then lands onthe flat outer surfaceof themanual actuator block I'IBa instead of, in front of said block. The paw1canonly be gotten in front of said block by the operator releasing thefoot treadle and allowing, th manual actuator I18 toreturn tonormalrAssumingnow that the operator desires to set the control mechanism for arepeating opera tion of the press, he swings the preselecting lever I981into the upper position illustrated in Figure 5.v This retractstheintercepting dog I93 toward the left into a position where itisoperative'to block a part of the motion of pawl I66; Hence, as; shownin Figure; 5, when the depression. of th treadle lever has oscillatedthemanual actue ator [18in a; counterclockwise direction, and has swung thepawl IGIr and clutch control member i64- beyond the center; line z-e,the block, I16 on the, pawl; I66 comesup against the. stop. shoulder I94of intercepter pawl, I93, This causes the, pawl I66- to oscillatethrough ashort rotative, throw around crank pin I64" as the crank; andcrank; pin complete their swinging movement toward the right. Thisoscillation of the motion transmitting pawl around the crank pin'swingsthe right hand nose I66" down out of the arcuate path of movement of thepower actuator block I'I9a; Accordingly, when the throw of the eccentricIOI starts oscillating the power actuator I19 in a downward, clockwisedirection the block I191: moves past the nose I 66" without transmittingany motion to the pawl I66; Hence, the power actuatorfdoes not functionto release the clutch for stopping the press after a: single stroke.Accordingly, the. clutch remains engaged and the press continues tooperate so, long as the intercepting pawl I93 remains in its elevatedposition, holding the motion. transmitting pawl I66 out of the'path. ofthe poweractuator. Said intercepting paw1 I93 will remain inv thisraised position as 10mg as the operator continues to hold his foot onthe treadle lever; As soon as the treadle lever is released the downwardmovement of th link" I32 and lifting pin I92" permits the intercepterpawl I93 to drop down to normal position, whereupon the motiontransmitting pawl I66 is quickly oscillated into its final position bythe biasing spring I61, in which final position the pawl nose I66" liesin the path of the. power actuator block H911 and hence has the motiontransmitted thereto from said block in th next downward oscillationof-the poweractuat'or. v

When the clutch is arranged so that the repeating operationisma'desubiect to automatic control exercised through plunger head 23I',such as. by the control rod 2 or its equivalent, the

intercepting pawl rea is held in this raised position after theoperatorreleases the treadle lever; The intercepter pawl remainsin this: raisedintercepting position so long as the plunger head 23I is' held? in itsraised position. Immediately upon the release of the head 23I',thelowerin of the pawl I93 permits the power actuator to transmit motionthrough the motion transmittingpawl for releasing the clutch and bringinclutch, control mechanism in such, condition that the operator can onlyefiect single stroke operation, without any possibility of hisv beingable: to

change over to repeating operation, allthat the plant superintendent hasto do is to'release' the housing cover I52 and entirely remove theintercepting dog I93 from the assembly by slidin the dog endwise off thepins I95 and 231. With this dog removed, there is nothing to interceptthe full throw of the motion transmitting pawl I66, and hence singlestroke operation cannot now be nullified or circumvented.

While I have illustrated and described what I regard to be the preferredembodiment of my invention, nevertheless it will be understood that suchis merely exemplary and that numerous modifications and rearrangementsmay be made therein without departing from the essence of the invention.

I claim:

1. In combination, a clutch, an oscillatory clutch control member, amanual actuator, a

power actuator, a double nose pawl pivotallymounted on said oscillatoryclutch control member and operative to transmit motion from said manualactuator to said control member through one nose and operative totransmit motion from said power actuator to said control member throughthe other nose, over-center spring means for causing said pawl to pivoton said clutch control member in the oscillatory movement of the latterfor bringing each nose of the pawl alternatively into position toreceive motion from .said actuators, and intercepting means adapted tointercept said pawl for holding one nose thereof out of the path of oneof said actuators.

2. In combination, a clutch, a member adapted to be driven thereby,clutch actuating mechanism, a first brake governing said clutchactuating mechanism, a second brake serving only to govern the motion ofsaid driven member, and control mechanism for jointly controlling saidbrakes and including means for causing one brake to operate at adiiferent time than the other brake.

3. In combination, a clutch comprising a shiftable clutch element, adriven member adapted to be driven by said clutch, clutch actuatingmechanism governing the shifting of said shiftable clutch element, afirst friction brake governing said clutch actuating mechanism, a secondfriction brake operative to exert braking retardation against the motionof said driven member, and control mechanism for automatically causingsaid brakes to operate substantially concurrently and including meansfor automatically causing said first brake to release slightly inadvance of said second brake.

4. In a punch press, the combination of a crankshaft for driving a pressram, a clutch for driving said crankshaft, clutch actuating mechanism, afirst brake governing said clutch actuating mechanism, a second brakeserving only to govern the motion of said crankshaft, and controlmechanism for jointly controlling said brakes including releasablecoupling mean for automatically causing one of said brakes to beactuated concurrently with the other brake or enabling it to be releasedtherefrom so as not to respond to said control mechanism when said otherbrake is operated.

5. In combination, a clutch, a driven member adapted to be driventhereby, clutch actuating mechanism, a first brake drum and a first setof brake shoes cooperating therewith for governing said clutch actuatingmechanism, a second brake drum and a second set of brake shoes comemberwithout exercising any control over said clutch actuating mechanism, andcontrol mechanism operative to effect common actuation of both sets ofbrake shoes or to effect actuation of only one of said sets of brakeshoes.

6. In combination, a clutch, a driven member adapted to be driventhereby, clutch actuating mechanism, a first brake governing said clutchactuating mechanism, a second brake serving only to govern said drivenmember, control mechanism for both of said brakes, and means forrendering said clutch incapable of engagement through said first brakewhile still leaving said second brake capable of holding said driven member at any desired angular positoin.

'7. In combination, a clutch, a member adapted to be driven thereby,clutch actuating mechanism, a first brake drum governing said clutchactu-- ating mechanism, a second brake drum governing the motion of saiddriven member, brake means adapted to engage said brake drums, and meansoperative to couple said brake drums together when it is desired torotate said driven member other than through said clutch.

8. In combination, a clutch, clutch actuating mechanism comprising abrake drum for governing said clutch, a plurality of brake shoes forengaging with said brake drum, spring means normally tending to engagesaid shoes against said drum, control means for releasing said brakeshoes, and spring take-up means effective between said control means andone of said brake shoes for enabling one of said brake shoes to moveinto eifective braking engagement with said brake drum even thoughanother of said brake shoes has earlier engaged said brake drum.

9. In combination, a clutch, clutch actuatin mechanism, a brake drumgoverning said clutch actuating mechanism, a pair of brake shoes adaptedto engage said drum, clutch control mechanism comprising a togglerocker, toggle links pivotally connected with said rocker, and

spring take-up devices establishing a one-way resilient coupling betweensaid toggle links and said brake shoes whereby substantially to equalizesaid brake shoes in the operation of engaging said brake drum.

10. A punch press comprising a ram, a crankshaft for reciprocating saidram, a clutch for driving said crankshaft, control mechanism thereforcomprising a motion transmitting member governing the operation of saidclutch, motion interrupting means for controlling the movement of saidmotion transmitting member, and automatic mechanism adapted to hold saidmotion interrupting means in a predetermined position until an abnormalcondition arises at the punch press, whereupon said motion interruptingmeans permits said motion transmitting member to op-' erate to disengagesaid clutch.

11. Ina punch press, the combination of a crankshaft, a clutch fordriving said crankshaft comprising drivin and driven clutch elements,clutch actuating mechanism, a brake for governing said clutch actuatingmechanism, a toggle rocker controlling said brake, a manual actuator foractuating said toggle rocker, a power actuator for actuating said togglerocker, and safety means operative upon predetermined overtravel ofsaidclutch for imparting further rocking motion to said toggle rocker andthereafter positively blocking the driven element of said clutch.

12. In combination, a driven member, a clutch for driving said drivenmember, torque responoperating therewith for governing said driven siverelease mechanism for releasing said clutch,

brake means governing the operation of said release mechanism, controlmechanism for said brake means comprising a rotary control member, arotary manual actuator, a rotary power actuator responsive to saiddriven member, said control member and said actuators being all mountedconcentrically on a stationary axis and being capable of independentrotative movement thereon, and pawl means pivotally mounted on saidrotary control member for alternatively establishing operativeconnection with each of said actuators.

13. In combination, a driven element, a friction clutch for driving saiddriven element comprising a shiftable clutch element. a set of forwarddriving struts pivotally mounted between said elements to transmittorque from one element to the other during forward rotation. a set ofreverse driving struts pivotally mounted between said elements totransmit torque from one element to the other during reverse rotation,both sets of said struts being solid, fixed length units havingspherical end heads seating in spherical sockets in said elements,compression springs surrounding said reverse driving struts and seatingagainst annular shoulders formed in said elements around the sphericalsockets which receive the reverse driving struts, said compressionsprings tending to cause relative rotation between said elements,ball-cam thrusting mechanism operative to transmit shifting pressure tosaid shiftable clutch element in a clutch releasing direction, brakemeans governing said ball-cam mechanism, a brake control member havingoscillatory movement, a manual actuator, a power actuator driven by saiddriven element, and a pawl pivotally mounted on said brake controlmember and adapted to establish engagement alternatively with saidactuators.

14. In combination, a clutch for controlling the drive to a drivenmember, clutch control mechanism comprising brake apparatus forcontrolling the engaging and releasing of the clutch, control mechanismfor controlling said brake apparatus comprising an oscillatory controlmember, an oscillatory manual actuator and an oscillatory power actuatorall mounted for independent oscillatory movement, means for transmittingmotion from said driven member to said power actuator, a motiontransmitting pawl pivotally mounted on said oscillatory control member,and spring means serving to exert an over-center biasing action inopposite directions on said oscillatory control member and also servingto swing said pawl in opposite "directions around its pivotal mountingon said control member.

15. In clutch mechanism, the combination of a driven member, a clutchfor driving said member comprising a clutch element shiftable into andout of clutching engagement, a brake, means responsive to said brake forshifting said clutch element, spring toggle mechanism adapted to bebiased to each side of a dead center position for operating said brake,said toggle mechanism applying said brake when biased to one side ofsaid dead center position and releasing said brake when biased into orto the other side of said dead center position, control mechanism forcontrolling said toggle mechanism comprising a control member, a manualactuator for actuating said control member in one direction, a poweractuator for actuating said control member in the opposite direction, amotion transmitting pawl pivotally mounted on said control member, andspring toggle means for swinging said pawl alternatively into and out ofengagement with said actuators.

16. In combination, a clutch, a pivotally swinging clutch controlmember, a pivotally swinging manual actuator, a pivotally swinging poweractuator, each of said pivotally swinging members being capable ofindependent pivotal motion, a motion transmitting pawl pivotally mountedon said control member adapted to be engaged alternatively by saidactuators, means for automatically swinging said pawl into itsalternative engaging positions, said pawl being constructed and arrangedwhereby it is physically impossible for it to be engaged by bothactuators simultaneously, and optionally operated means for holding saidpawl in a position where neither actuator can engage it.

17. In a clutch, the combination of a shiftable clutch element, a rotaryelement, cooperating pairs of forward driving spherical sockets carriedby said elements, solid fixed-length forward driving struts seated insaid forward driving sockets to transmit substantially the entireforward driving torque load from one-element to the other, cooperatingpairs of reverse driving spherical sockets carried by said elements,solid fixedlength reverse driving struts seated in said reverse drivingsockets, annular shoulders formed around said reverse driving sockets,and compression springs surrounding said reverse driving struts andseating on said annular shoulders.

18. In combination, a rotary driven member, a clutch for driving saiddriven member comprising a shiftable clutch element, a shiftable servostrut ring secured to said shiftable clutch element, a non-shiftableservo strut ring secured to said driven member, two sets of oppositelyfacing inclined spherical sockets machined out of said two servo strutrings, a set of forward driving servo struts seating in one set of saidsockets, and a set of backward driving servo struts seating in the otherset of said sockets and inclined relatively to said forward drivingstruts, the servo struts of both sets being solid one-piece units offixed length formed with spherical ends for seating in said sphericalsockets.

19. In combination, a rotary driven member, a clutch for driving saiddriven member comprising a shiftable clutch element, a shiftable servostrut ring secured to said shiftable clutch element, a non-shiftableservo strut ring secured to said driven member, two sets of oppositelyfacing inclined spherical sockets machined out of said two servo strutrings, a set of forward driving servo struts seating in one set of saidsockets, a set of backward driving servo struts seating in the other setof sockets, the servo struts of both sets being solid one-piece units offixed-length formed with spherical ends for seating in said sphericalsockets, annular shoulders formed around the set of sockets whichreceive said backward driving servo struts, and compression springssurrounding said backward driving servo struts and seating on saidannular shoulders.

CLARENCE M. EASON.

